Endogenous serum erythropoietin and no-reflow in patients with ST-elevation myocardial infarction

Advances in Coronary No-Reflow Phenomenon-a Contemporary Review

PURPOSE OF REVIEW

Coronary artery no-reflow phenomenon is an incidental outcome of percutaneous coronary intervention in patients presenting with acute myocardial infarction. Despite advances in pharmacologic and non-pharmacologic therapies, coronary no-reflow phenomenon occurs more commonly than desired. It often results in poor clinical outcomes and remains as a relevant consideration in the cardiac catheterization laboratory. In this systematic review, we have sought to discuss the topic in detail, and to relay the most recent discoveries and data on management of this condition.

RECENT FINDINGS

We discuss several pharmacologic and non-pharmacologic treatments used in the prevention and management of coronary no-reflow and microvascular obstruction. Covered topics include the understanding of pharmacologic mechanisms of current and future agents, and recent discoveries that may result in the development of future treatment options. We conclude that the pathophysiology of coronary no-reflow phenomenon and microvascular obstruction still remains incompletely understood, although several plausible theories have led to the current standard of care for its management. We also conclude that coronary no-reflow phenomenon and microvascular obstruction must be recognized as a multifactorial condition that has certain predispositions and characteristics, therefore its prevention and treatment must begin pre-procedurally and be multi-faceted including certain medications and operator techniques in the cardiac catheterization laboratory.

Usefulness of The C-Reactive Protein/Albumin Ratio for Predicting No-Reflow in ST-elevation myocardial infarction treated with primary percutaneous coronary intervention

BACKGROUND

The ratio of serum C-reactive protein (CRP) to albumin has been proven to be a more accurate indicator than albumin and CRP levels alone in determining the prognosis of patients with cancer and critical illness. The aim of this study was to determine whether the CRP/albumin ratio (CAR) can be linked to imperfect reperfusion that can worsen the prognosis of ST-elevation myocardial infarction (STEMI) in patients treated with primary percutaneous coronary intervention (pPCI).

MATERIALS AND METHODS

A total of 1217 consecutive STEMI patients who achieved epicardial vessel patency with pPCI were recruited to this study.

RESULTS

The study population was divided into 2 groups: reflow (n = 874) and no-reflow (NR) (n = 343) groups. The white blood cell count (WBC), neutrophil-to-lymphocyte ratio (NLR) and CAR (0.03 [0.01-0.04] vs 0.06 [0.03-0.12] (P < .001) were significantly higher in the NR group than in the reflow group, and these factors were found to be independent predictors of NR development. The best cut-off value of CAR predicting NR was 0.59 with a sensitivity of 54.7% and specificity of 86.7. The predictive power of CAR surpassed that of CRP, albumin, WBC count and NLR in the receiver operator curve (ROC) curve comparison.

CONCLUSION

No-reflow can be predicted by systemic inflammation markers including WBC count, NLR and CAR measured from the blood sample obtained on admission. CAR has a higher clinical value than CRP, albumin level, WBC count and NLR in NR prediction.

Pretreatment With Erythropoietin Attenuates Intestinal Ischemia Reperfusion Injury by Further Promoting PI3K/Akt Signaling Activation

BACKGROUND

Erythropoietin (EPO) has been shown to be beneficial in resolution of acute inflammation and intestinal ischemia/reperfusion (IR) injury is featured by the excessive immune response. The current research is designed to evaluate the effect and potential mechanisms of EPO on the intestinal IR injury. Therefore, the effect of EPO on intestinal IR injury was examined by the change of intestinal histology; the expression of pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interferon γ (IFN-γ); and the protein levels of EPOR, p-EPOR, p85, p-p85, Akt, p-Akt, IκΒ-α, p-p65, and p65.

MATERIALS AND METHODS

Thirty male Sprague-Dawley rats were randomly divided into three groups: sham group (sham), IR-saline group (IRI), and the IR-EPO group (EPO). Rats were treated with EPO (5000 U/kg) 1 hour before IR induction. A rat model of IR injury was established by ligating the superior mesenteric artery for 30 minutes, followed by reperfusion for 1 hour. Intestinal histology, pro-inflammatory cytokines, and mediators were assessed. The effect of EPO on PI3K/Akt/NF-κB signaling and EPOR were also measured.

RESULTS

EPO significantly decreased the pathologic changes of intestinal and reduced the elevation of pro-inflammatory cytokines TNF-α, IL-1β, and IFN-γ in intestinal and serum caused by IR which was associated with suppressing NF-κB activation by further promoting activation of PI3K/Akt signaling.

CONCLUSIONS

EPO ameliorated the acute intestinal injury caused by IR, which was associated with further activating PI3K/Akt signaling to suppress NF-κΒ-mediating inflammation. Our findings suggest that EPO could be useful for preventing IR-induced intestinal injury.

Inflammatory markers in ST-elevation acute myocardial infarction

After acute myocardial infarction, ventricular remodeling is characterized by changes at the molecular, structural, geometrical and functional level that determine progression to heart failure. Inflammation plays a key role in wound healing and scar formation, affecting ventricular remodeling. Several, rather different, components of the inflammatory response were studied as biomarkers in ST-elevation acute myocardial infarction. Widely available and inexpensive tests, such as leukocyte count at admission, as well as more sophisticated immunoassays provide powerful predictors of adverse outcome in patients with ST-elevation acute myocardial infarction. We review the value of inflammatory markers in ST-elevation acute myocardial infarction and their association with ventricular remodeling, heart failure and sudden death. In conclusion, the use of these biomarkers may identify subjects at greater risk of adverse events and perhaps provide an insight into the mechanisms of disease progression.

High-dose erythropoietin in acute ST-segment elevation myocardial infarction: a meta-analysis of randomized controlled trials

OBJECTIVE

We sought to perform a meta-analysis to evaluate the potential influence of high-dose erythropoietin (EPO) on cardiac function parameters in patients with acute ST-segment elevation myocardial infarction (STEMI).

METHODS AND RESULTS

By searching PubMed, EMBASE, and the Cochrane Library (up to December 2012), seven randomized controlled trials (RCTs) reporting cardiac functional parameters with a total of 1,250 acute STEMI patients were identified. When applied to patients with acute STEMI, high-dose EPO was relatively safe and no increase in all-caused death and severe adverse effects were indicated. Estimates were pooled from fixed or random effects models. Compared with controls, high-dose EPO resulted in a slight but significant improvement in left ventricular ejection fraction of 1.02 % [95 % confidence interval (CI) 0.17-1.88, P = 0.019, I (2) = 0 %] and an improvement in left ventricular end-systolic volume of -4.61 ml (95 % CI -7.64 to -1.58, P = 0.003, I (2) = 27.7 %).

CONCLUSIONS

Available evidence suggested that high-dose EPO has limited cardio-protective effects in patients with STEMI. However, considering the relatively short follow-up durations and small patient populations in the current RCTs, the effects of high-dose EPO on clinical outcomes in patients with STEMI need to be evaluated in larger prospective RCTs of longer duration.

Serum EPO and VEGF levels in patients with sleep-disordered breathing and acute myocardial infarction

Background

A high level of endogenous erythropoietin (EPO) may be associated with a smaller infarct size determined by the release of necrosis markers. Sleep-disordered breathing (SDB) is a well-known risk factor for cardiovascular diseases. In contrast, protective effects of SDB have also been described. The potential role of increased levels of EPO and vascular endothelial growth factor (VEGF) is suggested in this process. The study aimed to explore the EPO and VEGF serum levels in SDB and non-SDB patients during the acute phase of myocardial infarction.

Methods

Thirty-seven patients undergoing successful primary percutaneous coronary intervention in the acute myocardial infarction have been examined for the levels of EPO, VEGF, and troponin I (Tn). In the following, patients had an overnight polysomnography to determine breathing disturbances during sleep.

Results

Both on admission day (day 1) and day 3 of hospitalization, EPO levels showed statistically significant differences in both SDB-positive and SDB-negative patient groups (p = 0.003 and p = 0.018, respectively). There was no statistically significant difference in VEGF levels. No correlation was found between the EPO and Tn levels.

Conclusions

SDB patients tend to have higher levels of EPO during acute myocardial infarction. No statistically significant differences in VEGF levels were observed.

Prevention of β-amyloid degeneration of microglia by erythropoietin depends on Wnt1, the PI 3-K/mTOR pathway, Bad, and Bcl-xL

Central nervous system microglia promote neuronal regeneration and sequester toxic β-amyloid (Aβ) deposition during Alzheimer's disease. We show that the cytokine erythropoietin (EPO) decreases the toxic effect of Aβ on microgliain vitro. EPO up-regulates the cysteine-rich glycosylated wingless protein Wnt1 and activates the PI 3-K/Akt1/mTOR/ p70S6K pathway. This in turn increases phosphorylation and cytosol trafficking of Bad, reduces the Bad/Bcl-x_L complex and increases the Bcl-x_L/Bax complex, thus preventing caspase 1 and caspase 3 activation and apoptosis. Our data may foster development of novel strategies to use cytoprotectants such as EPO for Alzheimer's disease and other degenerative disorders.